CVE-2022-39248
Assigner: GitHub_M
Published: 2022-09-28T20:05:12
State: PUBLISHED
affected: product: matrix-android-sdk2
vendor: matrix-org
versions: status: affected
version: < 1.5.1
descriptions: value: matrix-android-sdk2 is the Matrix SDK for Android. Prior to version 1.5.1, an attacker cooperating with a malicious homeserver can construct messages that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. matrix-android-sdk2 would then additionally sign such a key backup with its device key, spilling trust over to other devices trusting the matrix-android-sdk2 device. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. matrix-android-sdk2 version 1.5.1 has been modified to only accept Olm-encrypted to-device messages and to stop signing backups on a successful decryption. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.
metrics: cvssV3_1: attackComplexity: LOW
attackVector: NETWORK
availabilityImpact: NONE
baseScore: 8.6
baseSeverity: HIGH
confidentialityImpact: NONE
integrityImpact: HIGH
privilegesRequired: NONE
scope: CHANGED
userInteraction: NONE
vectorString: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
version: 3.1
problemTypes: descriptions: cweId: CWE-322
description: CWE-322: Key Exchange without Entity Authentication
type: CWE
descriptions: cweId: CWE-287
description: CWE-287: Improper Authentication
type: CWE
source: advisory: GHSA-fpgf-pjjv-2qgm
discovery: UNKNOWN
title: matrix-android-sdk2 vulnerable to Olm/Megolm protocol confusion